Lucid mountall can cause unexpected hangs
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Release Notes for Ubuntu |
Invalid
|
Undecided
|
Unassigned | ||
Ubuntu |
Invalid
|
Undecided
|
Unassigned | ||
Bug Description
[filed on behalf of Stefan Bader]
The policy of mountall was changed recently to wait for all local filesystems
present in /etc/fstab on boot. This was done to fix problems with the async
boot which happened otherwise.
Unfortunately this causes entries like the folowing (which was used to have
special mount options for certain removable disks/USB sticks) to leave the
system boot hanging forever:
LABEL=xxx /mnt ext3 defaults,
This should at least be documented in the release notes, though probably some
more should be done. Here a collection of thoughts:
1) The current behaviour does not give any indication about the reason of the
hang and leave the user clueless about the problem. Would it be possible to
print a message like "Waiting for xxx to become available for mounting", maybe
after a certain timeout?
2) At least some case might be prevented when update-manager could check for
entries in /etc/fstab which are currently not mounted or present and add the
"nobootwait" option to those entries.
3) To recover from this I resorted to the following steps, which are a bit
scary:
* Press ESC to exit from plymouth, then wait until the system seems to be
hanging. Then press SYSRQ-I which kills all currently running tasks.
* [boot drops into a maintenance shell]
* In some case I had to use "reset" to bring the terminal into a sane state.
* Then edit /etc/fstab
* Leave and reboot with CTRL-D
Question: Would it not be better to have a boot option to either drop to
maintenance (with only / mounted) or limit the time that mountall will wait.
Those could then be documented as workarounds.
Changed in ubuntu-release-notes: | |
status: | New → Confirmed |
I was able to boot into the old kernel that the upgrade left and edit my fstab.
Here was my entry in /etc/fstab that caused Lucid to hang on boot.
/dev/sdc1 /media/usb vfat defaults 0 0
Adding a 'nobootwait' option fixes the problem.
/dev/sdc1 /media/usb vfat defaults,nobootwait 0 0
As the OP says there was no hint as to what the problem was. Luckily I know my way around Ubuntu fairly well and was able to get enough info to lead me here. I am afraid there will be many that might not be able to so easily find this bug report. So i agree with providing users with a little more accessible information on this problem.